Sleeve valves typically have a valve body defining an axial fluid flow passage. A stationary valve plug is commonly fixed within the valve passage and carries or defines a valve seat positioned on an upstream end of the plug. A slidable valve sleeve is positioned in the valve passage and can be selectively moved between a fully closed position with a downstream end of the sleeve borne against the valve seat and a fully opened position with the downstream sleeve end spaced a distance from the valve seat. Fluid can flow through the valve passage and the sleeve, around the valve plug, and exit an outlet of the valve.
This type of sleeve valve has a number of important performance characteristics such as fluid flow rate, fluid pressure, valve flow coefficient, as well as inherent, installed, and linear flow characteristic, among others.
Various flow characteristics can typically be determined or controlled by a number of factors including the size and shape or contour of the upstream end of the valve plug, the shape of the plug body beyond or downstream of the upstream end, and the passageway or orifice size and contour surrounding the valve plug. Other valve features can be designed and shaped to affect valve flow or performance characteristics as well, including contours of the valve sleeve outlet opening or the like. However, designing a particular valve plug shape is a common means to achieve a desired valve performance or flow characteristics.
A typical valve for a given system has a unique, non-replaceable valve sleeve and plug. If a different valve flow characteristic is desired for a particular valve or system, or if a valve seat or plug is damaged within a valve or system, it is necessary to remove and replace the entire valve assembly within the system. To change the flow characteristics or the valve plug, it has heretofore been necessary to swap the entire valve with a new or replacement valve.
Many valves used today are quite large, such as those used to control flow in massive water or petroleum pipelines. An ordinary valve in such a system can be several feet in diameter or larger. Substantially all of these large control valves are fabricated from steel and are thus extremely heavy and difficult to handle. If it is desired to repair or replace the valve plug of a sleeve valve for such a large fluid delivery system, the entire valve assembly must be removed and replaced. This requires that an entire new valve be transported to the sight and/or be readily available at the sight. This also requires that a number of valves be manufactured, assembled, and stored for use or transport when needed. Removing and replacing an entire valve can be very time consuming, costly, and labor intensive. Heavy equipment is usually required to lift out the damaged valve assembly and to drop in a replacement because of the size and weight of such valves. Significant system downtime can also result, especially where multiple valves require repair or replacement, such as to change system flow characteristics.
As indicated above, it is also sometimes desirable to change one or more valve performance or flow characteristics within a system in order to affect flow rates, to accommodate delivery of a different fluid, or other such reasons. Again, each valve of the system whose performance is to be altered must be replaced in its entirety, resulting in the same problems noted above.
Smaller scale fluid delivery systems also often utilize sleeve valves constructed as described above. It is sometimes desirable to change flow or performance characteristic, or to repair or replace components for these smaller valves and systems as well. Again, to adjust performance or flow characteristics or to repair a damaged valve assembly typically requires selecting an entire new valve and replacing the old valve with the new valve. This can be time consuming, require manufacture and storage of a number of different valves, and be rather costly, even for a smaller scale fluid delivery system and especially where multiple valves in the system are to be altered.
Also, each sleeve valve typically has predetermined performance characteristics based on the structural features of its valve components, such as the valve plug. To provide a valve having different performance characteristics requires manufacturing and assembling a valve with different components. A typical sleeve valve includes a valve body, a specific sleeve, a particular plug, and perhaps other components such as actuator parts that are each unique to the valve. Each separate part or component requires material and labor resources to fabricate the parts. Each valve must then be separately assembled, stored, and shipped by the valve manufacturer. A manufacturer, distributor and/or an end user must also store, catalogue, and maintain each valve assembly separately, if having a variety of valves with different flow or performance characteristics on hand is desired.